JPS60128079A - Steering force control device in power control device - Google Patents

Abstract

PURPOSE:To reduce energy loss, by connecting a pressure generating chamber with a reaction chamber in a fluidically closed circuit condition to control the pressure of a pressure chamber in association with variations in the pressing force of a spool. CONSTITUTION:There is connected a control circuit 70 for controlling the amout of current fed to a solenoid 60, and the control circuit 60 is connected with a vehicle speed sensor 72 issuing a vehicle speed signal in accordance with a vehicle speed. A spool 61 is attracted downward in accordance with the amount of current, that is, the larger the amount of current, the smaller the attraction force of the spool 61. Hydraulic oil in a closed loop circuit is pressurized by the attraction force of the spool 61, and this pressure acts upon a plunger 54. When the vechile speed is high, the amount of current applied to the solenoid 60 is large so that a relatively large attraction force of the spool 61 acts upon the plunger 54 which therefore, receives a high pressure. When the vehicle speed is low, the plunger 54 can only receive a low pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a steering force control device for a power steering device including a reaction force chamber that controls the steering force according to the running state of a vehicle.

<Prior art> Conventionally, depending on the driving condition of the vehicle, the driver is given a light steering force when driving at low speeds, and a steering feel that does not flutter when driving at high speeds. There is a steering force control device for a power steering device that includes a reaction force chamber that applies a reaction force to a valve of a servo mechanism that distributes pressure fluid to left and right cylinder chambers of a power cylinder so as to apply a heavy steering force when driving. In this system, the pressure supplied to the pressure chamber from a power steering pump driven by the engine is controlled by a pressure control valve that is controlled according to a signal from a vehicle speed sensor, and the steering force is controlled according to the vehicle speed. That's what I do.

However, with such a configuration, there is a problem in that the horsepower required to drive the pump increases due to the pressure increase in the pressure chamber during high-speed running, resulting in large energy loss.

<Object of the Invention> In order to solve the above-mentioned problems, the object of the present invention is to control the steering force according to the running condition of the vehicle, and to control the reaction force chamber without using the rotational power of the engine. It is an object of the present invention to provide a steering force control device for a power steering device that can control pressure and has little energy loss.

<Structure of the Invention> The steering force control device for a power steering device according to the present invention changes the pressing force of a spool slidably guided in a pressure generating chamber formed in a main body according to the running state of the vehicle. The pressure generating chamber and the reaction force chamber are fluidly connected in a closed circuit in order to control the pressure in the pressure chamber according to changes in the pressing force of the spool.

<Example> Embodiments of the present invention will be described below based on the drawings.

A valve housing 12 is fixed to a housing body 11 that forms the main body of the power steering device. A pinion shaft 21 is rotatably supported within the housing body 11 and the valve housing 12 via a pair of bearings 13, 14, and a rank shaft that is slidable in a direction crossing the pinion shaft 21. 22 rack teeth 22a are in mesh with each other. This rack shaft 22 is connected to a piston of a power cylinder (not shown), and both ends thereof are connected to steering wheels via a required steering link mechanism.

A control valve mechanism 30 is housed within the hole of the valve housing 12. The control valve mechanism 30 has an input shaft 2 as a steering shaft.
The main components are a rotary valve member 31 integrally formed with the rotary valve member 3, and a sleeve valve member 32 fitted concentrically and relatively rotatably to the outer periphery of the rotary valve member 31. The rotary valve member 31 is flexibly connected to the pinion shaft 21 via a torsion bar 24 which has one end connected to the input shaft 23 and the other end connected to the pinion shaft 21 . Although not shown, a plurality of lands and grooves extending in the axial direction are formed at equal intervals on the outer periphery of the rotary valve member 31, and a communication passage 37 that communicates from the bottom of the groove to the inner periphery. is drilled. A passage 39 is provided on the input shaft 23 to communicate the discharge boat 36 with a low pressure chamber 38 within the valve housing. On the other hand, a plurality of lands and grooves extending in the axial direction are formed at equal intervals on the inner circumference of the sleeve valve member 32, and distribution holes 40, 41 are provided that open from each groove to the outer circumference of the sleeve valve member 32. ing. When the control valve is in the neutral state, the pressure fluid supplied from the supply boat 35 flows evenly into the grooves on both sides of the land portion, passes through the communication passage 37 and the passage 39, and is discharged from the low pressure chamber 38 to the discharge port 3.
6. In this case, the power cylinders are not activated because the redistribution bows 33 and 34 are at low and equal pressures.

If the control valve deviates from its neutral state, one distribution hole 40 or 41 is supplied with pressure fluid and the other distribution hole 40 or 4 is supplied with pressure fluid.
1, the fluid discharged from the power cylinder flows into the discharge port 36 through the communication passage 37, passage 39, and low pressure chamber 38.
It is designed to be released in

A protrusion 50 that protrudes on both sides in the radial direction is formed at the end of the pinion shaft 21 of the rotor valve member 31 . A fitting groove 51 that is loosely fitted so as to be rotatable by several angles around the axis. is formed. The outer peripheral surface of the protrusion 50 has a V
An engagement groove 525- in the shape of
1 has an insertion hole 5 in the radial direction at a position corresponding to the engagement groove 52.
3 is formed. A plunger 54 that engages with the engagement groove 52 is inserted into the insertion hole 53 so as to be slidable in the radial direction.
An annular groove 55 is formed in the protrusion 50 to guide hydraulic oil to the rear of the plunger 54. Insertion hole 53 and annular groove 5
5 constitutes a reaction force chamber 56.

60 is a solenoid, and a spool 61 that is sucked downward by the solenoid 60 is slidably guided in the vertical direction by the inner circumference of the solenoid 60 and the valve body 62, and the spool 61 is balanced in the vertical direction by a spring. There is. A solenoid valve 63 consisting of a solenoid 60, a spool 61, and a valve body 62 is fixed to the valve housing 12. A flow passage 65 is formed in the valve housing 12 to slidably guide the spool 61 (a pressure generation chamber 64 formed in the valve body 62 is communicated with the annular groove 55, and the flow passage 65 and the pressure generation chamber 64, hydraulic oil is sealed in the reaction force chamber 56, thereby forming a closed circuit.

Note that the chamber above the spool 61 is communicated with the atmosphere.

A control circuit 70 that controls the magnitude of the current applied to the solenoid 60 is connected to the solenoid 60, and a vehicle speed sensor 7 that generates a vehicle speed signal according to the vehicle speed is connected to the control circuit 70.
2 are connected.

Next, control of steering force will be explained based on the above-described configuration. A vehicle speed signal corresponding to the vehicle speed is transmitted from the vehicle speed sensor 72 to the control circuit 70, and a current having a magnitude corresponding to the vehicle speed signal is applied from the control circuit 70 to the solenoid 60. The spool 61 is attracted downward depending on the magnitude of the current,
The attraction force of the spool 61 increases as the current increases. The hydraulic oil in the closed circuit is pressurized by the suction force of the spool 61, and this pressure acts on the plunger 54! When the vehicle speed is high, the current applied to the solenoid 60 is large, and a large suction force acts on the spool 61, so that a large pressure is obtained on the plunger 54. Conversely, when the vehicle speed is low, the current applied to the solenoid 60 is small, so only a small pressure can be obtained in the plunger 54. Therefore, when the vehicle speed is high, the force of the plunger 54 to restrict relative rotation between the rotary valve member 31 and the sleeve valve member 32 is large, and a large steering force is required as input from the handle to push the plunger 54 up.

On the other hand, when the vehicle speed is low, the force of the plunger 54 to restrict the relative rotation between the rotary valve member 31 and the sleeve valve member 32 is small, and a small steering force is required as input from the handle to push up the plunger 54. In this way, the steering force is controlled according to the vehicle speed.

While the relative rotation between the rotary valve member 31 and the sleeve valve member 32 is locked by the plunger 54, the power cylinder does not work, so the handle must be operated manually, and the plunger 54 is pushed up and the rotary valve member 32 is locked.
The power cylinder is operated only when the sleeve valve member 1 and the sleeve valve member 32 are rotated relative to each other.

Although the embodiment described above is applied to a rotary type control valve, the present invention may also be applied to a spool type control valve in which a spool valve member pivots relative to a sleeve valve member.

Furthermore, in the above embodiment, a solenoid is used to operate the spool, but a feed motor is used to displace the movable shaft, and the displacement of the movable shaft changes the pressing force on the spool via a spring. You can also do it.

Furthermore, the pressure in the reaction force chamber may be controlled according to the handle angle or the handle angular velocity.

A pressure generating chamber may be formed in the valve housing, and the spool may be slidably guided in the pressure generating chamber.

<Effects of the Invention> As described above, in the present invention, the spool is slidably guided in the pressure generating chamber formed in the main body, and the spool is pushed by the electric pressing force changing means according to the driving condition of the car. The pressure generating chamber and the reaction force chamber are fluidly connected in a closed circuit in order to change the pressure and control the pressure in the reaction force chamber according to changes in the pressing force of the spool, and the pressure required in the reaction force chamber is adjusted. Since the electric pressure changing means is operated in response to the pressure change, an advantage of less energy loss can be obtained.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of a rotary control valve using a solenoid valve, showing an example of an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 11...Housing body, 12...Valve housing,
21... Pinion shaft, 22... Rack shaft, 23...
- Input shaft, 24... Torsion bar, 31... Rotary valve member, 32... Sleeve valve member, 50... Projection, 51... Fitting groove, 52... Engaging groove, 53...
- Insertion hole, 54... plunger, 55... annular groove,
56... Reaction force chamber, 60... Solenoid, 61...
Spool, 62... Valve body, 64... Pressure generation chamber,
65... Flow path, 70... Control circuit, 72... Vehicle speed sensor. Patent applicant Toyota Machinery Co., Ltd. -10=

Claims (1)

[Claims] (11) In a power steering system equipped with a reaction force chamber that controls steering force, a control device that generates an output in response to the running state of the vehicle is provided, and a spool is slidably guided to a pressure generation chamber formed in the main body. An electric pressing force changing means is provided for changing the pressing force of the spool in accordance with the output of the control device, and the electric pressing force changing means is provided so as to react with the pressure generating chamber in order to generate a pressure in the reaction force chamber corresponding to a change in the pressing force of the spool. A steering force control device for a power steering device, characterized in that the device is fluidly connected to a power chamber in a closed circuit.